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Finding the Fourth Proportional to 81.96, 123.20 and 70.60

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Solution

The fourth proportional to 81.96, 123.20 and 70.60 is: 106.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.96 : 123.20 = 70.60 : x
  2. Step 2: Convert to fraction form
    81.96/123.20 = 70.60/x
  3. Step 3: Cross multiply
    81.96x = 123.20 × 70.60
  4. Step 4: Simplify right side
    81.96x = 8,697.92
  5. Step 5: Solve for x
    x = 8,697.92/81.96
  6. Step 6: Final answer
    x = 106.12

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.